Solve for x in this triangle

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

Segment xz is bisected by point y. if xy = 12x, and the measure of xz = 18x – 6, solve for x

Look at attachment. has all info needed. need